Loads for bolt gun vs. AR?

[John Klingenberg]

My question is this; SAAMI approves a cartridge that's basically intended for an AR platform so its pressure is generally loaded to the 50,000/55,000+ psi range. Can that same cartridge be loaded slightly higher in a modern bolt action. I ask because I'm loading a 224 Valkyrie for a Savage bolt gun and it's slightly slower than published velocities at max published data. My book says 52,000 psi for a max load of 24 grains of CFE 223 behind a 90 grain Berger VLD. It's supposed to give me 2617fps. I was getting 2589. The test barrel is 24" and mine is a 26" Hart. I did a few test loads working up to 25 grains and get to 2789 which is more in line where I think it should be. I have zero pressure signs. Primers are nice and round, no puckering at the firing pin, no bolt lift problems, no case stretching, no ejector swipe/mark. I've been loading for 40 years but I've never gone over book. Am I being overly paranoid here? How far can I go with this? Thanks for any inputs.

 

[mtwarych]

I think going over book max is fine to do IF you are working up slowly and carefully.

My 7mm is 3 grains over book max, like you, I have no signs of pressure or danger.

It sounds like you know what you are doing, I say go ahead and work up your load safely.

Sometimes overthinking is a good, safe thing to do.

 

[Zen Archery]

I work with a lot of wildcats that have no printed data. In theory, yes you can push bolt gun more. Just look for signs of concerns - primers, case, ejection marks, etc.

 

[westcliffe01]

With a semi, the chambering and extraction are rather more brutal than in a bolt gun. Which is why I'm not really considering a semi for my long range firearms. The exception is if you have an adjustable gas port and can turn the gas off for your "special ammo". I don't need the tip of the bullet smashed into the feed ramp, nor do I want the special brass flung 10 ft away in the tall grass...

Depending on the barrel length and port position, the gas pressure may be significant at the point when the bolt is trying to extract the case from the chamber thus the cartridge rim may get mangled too. Its just not my cup of tea...

 

[John Klingenberg]

I'm not much on the AR except for social work. The rest of the time my bolt guns are my go to.

 

[John Klingenberg]

I appreciate the input folks. I have to say I really like this cartridge at 2800 fps with a 90 grain. It does have some hang time.

 

[westcliffe01]

I bought a Shilen barrel with a Wylde chamber but unfortunately the throat is way too short to accommodate the 80gr VLD I was planning on using. So I need to find a gunsmith who could deepen the throat for me or come up with another way to lengthen the throat. It makes my skin crawl to consider the lapping bullets offered by some LR enthusiasts but that may be a legitimate process for this scenario where my throat is too short. Im just worried that a typical gunsmith would make a hash of lengthening the throat and ruin a brand new barrel...

 

[John Klingenberg]

I bought a Shilen barrel with a Wylde chamber but unfortunately the throat is way too short to accommodate the 80gr VLD I was planning on using. So I need to find a gunsmith who could deepen the throat for me or come up with another way to lengthen the throat. It makes my skin crawl to consider the lapping bullets offered by some LR enthusiasts but that may be a legitimate process for this scenario where my throat is too short. Im just worried that a typical gunsmith would make a hash of lengthening the throat and ruin a brand new barrel...

Send it off to a reputable Smith. A piloted throater is fairly easy to run. You could probably do it by hand with a rented setup. Load up a few dummy cartridges at the depth you want the Smith to throat it and send it along with your barrel.

 

[Longshotjames]

for the OP: yes in theory a modern bolt can be pushed more than book. However each chamber is different and one my build pressure quicker than others. The brass you use can also be a big factor in pressure vs powder capacity.

In your case start stepping up in .3 or .5 grain increments until you start to see signs of pressure and then back down one step.

I bet that Hart barrel will get you more velocity!!!
James

 

[John Klingenberg]

Thanks for the inputs everyone.

 

[nksmfamjp]

That should basically be step 1 of load development. At a given set of dimensions I run from min to maxish to find a max load or reasonable max velocity.

 

[John Klingenberg]

It's what I would normally do, I just thought I wasn't getting the full potential out of this cartridge. I have never gone over book before but the published data is begging to be challenged for this cartridge in bolt guns.

 

[nksmfamjp]

I load until I see signs of pressure and then back off. With the right increments, there is little risk because the actions should be designed for fatigue so yield or uts failures should be much higher pressure.